efi_loader: correct function comment style

Replace @return and @param.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
diff --git a/lib/efi_selftest/efi_selftest_startimage_exit.c b/lib/efi_selftest/efi_selftest_startimage_exit.c
index 5d4c0a6..b65a10b 100644
--- a/lib/efi_selftest/efi_selftest_startimage_exit.c
+++ b/lib/efi_selftest/efi_selftest_startimage_exit.c
@@ -79,7 +79,7 @@
  *
  * @handle:	handle of the loaded image
  * @systable:	system table
- * @return:	EFI_ST_SUCCESS for success
+ * Return:	EFI_ST_SUCCESS for success
  */
 static int setup(const efi_handle_t handle,
 		 const struct efi_system_table *systable)
@@ -96,7 +96,7 @@
 /*
  * Tear down unit test.
  *
- * @return:	EFI_ST_SUCCESS for success
+ * Return:	EFI_ST_SUCCESS for success
  */
 static int teardown(void)
 {
@@ -117,7 +117,7 @@
  *
  * Load and start the application image.
  *
- * @return:	EFI_ST_SUCCESS for success
+ * Return:	EFI_ST_SUCCESS for success
  */
 static int execute(void)
 {